How are washing powder and soap made?

According to historical records, the earliest soap formula originated in Mesopotamia, West Asia. About 3000 BC, people mixed 1 part oil and 5 parts alkaline plant ash to make a detergent. There are many legends about the origin of soap in Europe. Speaking of Gauls in ancient Rome, sheep oil and beech ash solution were stirred into a thick shape every holiday, applied to hair and combed into various hairstyles. Once a festival was caught in heavy rain, and the hairstyle was ruined, but people unexpectedly found that the hair became clean. It is also said that when the Romans sacrificed to the gods, the fat of roasted cattle and sheep dripped into the plant ash, forming a "grease ball". When women wash clothes, they find that clothes stained with "oil balls" are easier to clean. This shows that people have used animal fat and plant ash soap for thousands of years.

Archaeologists discovered a soap-making workshop in the ruins of Pompeii, Italy. This shows that the Romans had already started the primitive soap production as early as the 2nd century AD. China people have long known that plant ash and trona are used for washing clothes. People also mix pig pancreas and lard with natural pork to make a lump called "pancreas".

Early soap was a luxury. Until 179 1, French chemist Lublan successfully made caustic soda from electrolytic salt at a low price, thus ending the ancient method of making caustic soda from plant ash. 1823, German chemist Cheever discovered the structure and characteristics of fatty acids, and soap is one of them. /kloc-at the end of 0/9, the soap-making industry finally transformed from a manual workshop to industrial production?

Soap can decontaminate because it has a special molecular structure. One end of the molecule is hydrophilic and the other end is lipophilic. At the interface between water and oil, soap emulsifies oil and dissolves oil in soapy water. At the interface between water and air, soap surrounds air molecules to form soap bubbles. The dirt that was originally insoluble in water can no longer adhere to the surface of clothes because of the action of soap, but is dissolved in soap foam and finally washed away completely.

/kloc-in the 0/8th century, the French made "artificial soda" from salt and Carboniferous to replace the traditional alkali juice extracted from ashes. /kloc-in the 0 th and 9 th centuries, the Germans invented sodium hydride by electrolyzing salt water; Since then, the popularity of caustic soda has changed soap from a commodity that only the nobles in the palace can afford to a daily necessities for ordinary people.

Before that, the manufacture of soap depended on experienced craftsmen. It is prepared with oil-alkali ratio juice, because there is no information to refer to, and it is often tried again because it cannot be solidified.

It is worth mentioning that in the United States during the pioneer period, immigrants would choose warm days in early spring and gather the whole village to make soap.

The material source of soap is the astringent juice extracted from oak, beech and other wood as the source of alkali juice. If it is not enough, supplement it from the ashes of the heater. With alkaline juice, we can get oil from animal fat or vegetable oil for cooking, but once the oil and water are separated, we have to start all over again. Only in the19th century did enterprises invest in the production of soap.

Why is it called soap

Because the ancients used Gleditsia sinensis to wash clothes in the Yellow River valley, and there were no Gleditsia sinensis trees in the Yangtze River valley, they found a tree with the same performance as Gleditsia sinensis, which can also wash clothes, but it is more plump than Gleditsia sinensis, so they named her Gleditsia sinensis, also called Gleditsia sinensis fruit.

Later, when artificial detergents were invented, the word "soap" was still used.

Therefore, although there is no thin soap, there is a non-fat soap, namely "Gleditsia sinensis".

Soap (called Fan Jian in Guangdong) is a kind of surfactant used as personal cleaning products, which usually exists in solid blocks.

history

In ancient times, regardless of the east and west, the earliest washing ingredients were nothing more than sodium carbonate and potassium carbonate. The former is the product of natural lake minerals, and the latter is the main washing component of plant ash. The invention of soap is said to be Phoenician on the east coast of the Mediterranean. Legend has it that in a palace in ancient Egypt in the 7th century BC, a Phoenician chef accidentally knocked over a can of cooking oil. He was scared, so he quickly sprinkled the plant ash in the stove on it without anyone noticing, and then took it out and threw it away with his hand.

Looking at his greasy hands, he thought: I don't know when I can wash such dirty hands! He hesitated and put his hand in the water. Miracle happened: he just rubbed it a few times, and his greasy hands were easily washed off! Even the old dirt that was difficult to wash away was washed away. This cook was very strange, so he asked other chefs to taste this gray oil. As a result, everyone's hands are cleaner than before. Therefore, servants in the kitchen often wash their hands with oil and plant ash. Later, Lao Wang also knew the secret and asked the chef to make some plant ash oil to wash his hands.

Of course, legends are just legends after all, and they may not be completely taken seriously. But the Egyptian lake near Alexandria is rich in natural sodium carbonate, so the washing technology in ancient Egypt is relatively developed, and it is not surprising that soap was invented.

soap

It is the general name of fatty acid metal salts. The carbon number of fatty acids in daily soap is generally 10- 18. Metals are mainly alkali metals, such as sodium or potassium, but there are also ammonia and some organic bases, such as ethanolamine and triethanolamine, which are used to make soaps for special purposes. Soaps include laundry soap, soap, metal soap and liquid soap, as well as fatty acids, hardened oil and glycerol and other related products.

Soap contains not only higher fatty acid salts, but also fillers such as rosin, water glass, spices and dyes. Structurally, higher fatty acid sodium molecules contain nonpolar hydrophobic part (hydrocarbon group) and polar hydrophilic part (carboxyl group). Hydrophobic groups are lipophilic. When washing, the grease in the dirt is stirred and dispersed into fine oil droplets. After contacting with soap, hydrophobic groups (alkyl groups) of higher fatty acid sodium molecules are inserted into oil droplets and combined with oil molecules by van der Waals force. The hydrophilic group (carboxyl group) easily soluble in water partially extends out of the oil drop and is inserted into the water.

In this way, oil droplets are surrounded by soap molecules, dispersed and suspended in water to form emulsion, and then washed away by water through friction and vibration. This is the principle of soap decontamination. But ordinary soap should not be used in hard water or acidic water. Water-insoluble calcium stearate and magnesium stearate are formed in hard water, and water-insoluble fatty acids are formed in acidic water, which greatly reduces the decontamination ability.

Type of soap:

Soap has a wide range of uses, besides the familiar washing clothes, it is also widely used in the textile industry. Sodium salts of higher fatty acids are commonly used, which are generally called hard soaps; Its potassium salt is called soft soap, which is mostly used for washing hair and shaving. Its ammonium salt is usually used to make vanishing cream. According to the composition of soap, considering the fatty acid part, the soap made of fatty acid with high saturation is hard; On the contrary, soaps made of fatty acids with higher unsaturation are softer. The main raw material of soap is oil with high melting point. Considering the length of carbon chain, generally speaking, the carbon chain of fatty acid is too short, and the soap made is too soluble in water; If the carbon chain is too long, the solubility is too small. Therefore, only potassium or sodium salts of fatty acids of C 10~C20 are suitable for making soap. In fact, the most common soap is C 16~C 18 fatty acid sodium salt.

Soap usually contains a lot of water. Various soaps can be obtained by adding fillers such as spices and dyes into the finished products.

Commonly used yellow laundry soap is usually mixed with rosin, which is added in the form of sodium salt to increase the solubility and foaming of soap, and it is also cheaper as a filler.

White laundry soap is added with sodium carbonate and sodium silicate (the content can reach 12%), and the water content of general laundry soap is about 30%. If the white laundry soap is dried and sliced, you can get soap chips, which can be used to wash high-grade fabrics.

Adding a proper amount of mixture of phenol and cresol (antiseptic and bactericidal) or boric acid into soap to make medicated soap. Soap needs high-grade raw materials, for example, the soap made by mixing butter or palm oil with coconut oil is crushed, dried until the water content is about 10 ~ 15%, then spices and dyes are added, and pressed and molded.

Liquid potassium soap is often used as shampoo. , usually made of coconut oil.

Soap making process:

The basic chemical reaction of soap making is the interaction between oil and alkali to produce soap and glycerol;

The soap obtained by the reaction is called soap base after salting out, washing and finishing, and then processed into soaps of different commercial forms.

Refining removes impurities from oil. Common refining processes include decoloration, alkali refining (deacidification) and decoloration. Degumming is a hydration method to remove phospholipids and other colloids from oil, including hydration of phospholipids and other colloids with water, and then precipitation. And an acid refining method for carbonizing and precipitating phospholipids and similar impurities with concentrated sulfuric acid. The main function of alkali refining is to remove free fatty acids from oil, but due to the formation of flocculent soap and adsorption, pigments and impurities in oil are removed.

Saponified oil reacts with alkali after refining. The saponification method is mainly boiling, and the soap pot is cylindrical or square.

In addition, there are pipelines for transporting grease, lye, water and salt water. It is also equipped with direct steam or steam coil to introduce steam and stir soap. The pot is also equipped with a shaking tube, and the upper opening of the tube can be placed at any liquid level to discharge the soap in the pot. The bottom of the pot is conical, and there is a discharge pipe below it, which is used to discharge the residual liquid left by the discharge of the shaking pipe. Boil the grease and caustic soda in a soap pot until the saponification rate reaches about 95%, and stop saponification operation when the soap material is evenly closed.

Salting out in the closed soap material, adding salt or saturated brine, and separating the soap material from dilute glycerin water. The lowest concentration that makes soap precipitate is called salting-out limit concentration. After the closed soap gum is salted out, the upper soap is called soap particles; The glycerin water with salt in the lower layer is discharged from the bottom of the soap pan, and the glycerin is recovered.

After cleaning the waste liquid, add water and steam to boil the soap particles, so that they can change from the separated state into uniform soap gum, and wash away the residual glycerin, pigment and impurities.

Alkali precipitation is to completely saponify the residual oil in the soap particles, and then further wash away the glycerin, salt, pigment and impurities in the soap particles through alkali precipitation. The lowest alkali concentration for complete precipitation of alkali submerged water is called the limit concentration of alkali submerged water.

Adjust the contents of electrolyte and fatty acid in soap particles after alkali precipitation, reduce impurities, improve color, and obtain the maximum soap yield and qualified soap base. Appropriate amount of electrolyte (such as caustic soda and salt) should be added during finishing, and it should be adjusted enough to separate soap into two soap phases. The upper layer is pure soap base and the lower layer is soap foot. Soap feet are darker in color and contain more impurities, so they are generally reused when the pot is alkali-precipitated.

The molded soap base is concentrated into a large soap board, then cut into soap blanks, printed and dried into laundry soap, soap and other products.

[Edit] Composition

The main component is sodium stearate, and the molecular formula is. If spices and dyes are added to it, it will make soap with good color and flavor; If you add some drugs (such as boric acid or carbolic acid), it becomes a medicated soap.

[Edit] Decontamination principle

The molecular structure of soap can be divided into two parts. One end is the charged polar chief operating officer-(hydrophilic site), and the other end is the nonpolar carbon chain (lipophilic site). Soap can break the surface tension of water. When soap molecules enter water, the hydrophilic part with polarity will destroy the attraction between water molecules, reduce the surface tension of water, and make water molecules almost evenly distributed on the surface of clothes or skin to be cleaned. The lipophilic part of soap goes deep into oil stains, while the hydrophilic part is soluble in water. After stirring, this combination forms smaller oil droplets, the surface of which is covered with the hydrophilic part of soap, and will not recombine to form large oil stains. If this process (also called emulsification) is repeated many times, all the oil stains will become very tiny oil droplets dissolved in water and easily washed away.

[Edit] Using

Clean the body: soak the place to be cleaned with water, then apply soap there and wipe it clean with your hands.

Clean clothes: Soak clothes with water, apply soap to the dirt of clothes, and then wipe clothes with each other, so that clothes are clean.

[Editor] Famous brands

Ivory soap (ivory)

Comfort (safety)

strong man